How do I view the different texture paint of multiple objects simultaneously?
In order to view multiple textures simultaneously, change the viewport shading mode to either Material Preview or Rendered. Material Preview will allow you to view all of the materials in a scene and Rendered will provide a preview of what the rendered scene will look like.
To switch modes, use the four icons located at the top right hand corner of the viewport. The modes (from left to right) are Wireframe, Solid, Material Preview, and Rendered.